8/12/2019 Timilshina (2013) Microbial Assessment of Bottled Drinking Water of Kathmandu Valley

1/3

84

ABSTRACT

INTRODUCTION: Due to increased demand and

consumption of bottled water in Kathmanduvalley, there has been a growing concern about the

microbiological quality of this product. The

objective of this study was to assess the microbial

contamination of heterotrophs and total coliform.

MATERIALS AND METHODS: This cross sectional

study was done in randomly selected 30 different

commercial brand of bottled water available in

commercial market of Kathmandu valley, Nepal.

Total coliform and heterotrophic bacteria were

enumerated by the membrane filtration and

spread plate technique, respectively.

RESULTS: 90% (n=27) samples showed the

heterotrophic bacterial count above the

acceptable range (

8/12/2019 Timilshina (2013) Microbial Assessment of Bottled Drinking Water of Kathmandu Valley

2/3

Figure 1. Heterotrophs i

Microbiological contamination of bottled drinking water

Water-borne diseases are among the most recent

emerging and re-emerging infectious diseases,

which have been the biggest health threat

worldwide and they contribute between 70-80% of

health problems in developing countries.1 In Nepal,

morbidity and mortality rates from water borne

disease are considered high particularly among

children below the age of 5 years and

immunocompromised individual.2 Drinking water

is, however, not sterile and are contaminated by

microorganisms. Microbial contamination of

drinking water thus remains a major threat hence

constant vigilance is indispensable especially in

underdeveloped country like Nepal.3

Heterotrophic bacteria are non coliform species of

bacteria that utilizes organic substance for its

development. The presence of heterotrophic

bacteria in drinking water is not an indication that

the water presents the health risk but poses

significant risk in immunocompromised individuals.

Similarly, total coliform bacteria may cause special

health risk for infants, young children some elderly

people and especially to the immunocompromised

people.4 Purpose of this study was to assess bottled

drinking water for microbial contaminationby

enumerating heterotrophs and total Coliforms.

The study was conducted in Genesis Laboratory and

Research Centre, Kathmandu, Nepal from July 2012

to September 2012. Thirty different commercial

brands of marketed bottled water (name not

mentioned) samples were randomly collected from

the Kathmandu valley. The samples were analyzed

on the same day immediately after its delivery.

When immediate analyses were not possible, the

samples were preserved at 40C. Total coliforms

were enumerated by the membrane filtration (MF)

technique and culture on M-Endo agar for the

detection of the total coliforms. Heterotrophic

bacterial count was done by spread plate techniques

on plate count agar media. Bottled water was

defined as any portable water that was bottled and

distributed or offered for sale and specifically

intended for human consumption.5 Te criteria of

WHOs bottled drinking water quality specifications

world-wide was used for the interpretation of

results which says that the recommend total

coliform should be 0 cfu/ml and heterotrophic plate

count (HPC) limits

8/12/2019 Timilshina (2013) Microbial Assessment of Bottled Drinking Water of Kathmandu Valley

3/3

Int J Infect Microbiol 2012;1(2):84-86

study.3

The presence of high numbers of heterotrophic

bacteria in bottled water may be due to the natural

microbial flora present in the water. These bacteria

can multiply after bottling, resulting in high

numbers of heterotrophss.5 Another aspect is that

though heterotrophs are naturally present in all

aqueous environments but an abrupt increase

sometimes concurrently be associated with fecal

contamination.3 The presence of coliform in bottled

water indicates the exposure of water to the

external environment, as coliforms widely spreads

in the environment or insufficient processing during

bottling. Total coliform bacteria are easily destroyed

during processing and their presence in water

leaving a drinking water treatment plant indicates a

serious treatment failure.9

The presence of heterotrophs and the coliform in

the bottled water is a serious concern for public

health. The child population whose immune system

is weak or immunocompromised adults who

consumes the bottled water rich in heterotrophs

they can be seriously ill. The presence of coliform in

the drinking water is an indicator of poor quality of

drinking water and this can also pose the population

to serious health hazards. Concerned authority

should prioritize this issue and continuously

monitor the quality of mushrooming bottled water

manufacturers in Kathmandu valley to provide safe

drinking water to the population.

CONFLICT OF INTEREST:None to declare.

FINANCIAL INTEREST:None to declare.

REFERENCES

1. Jayana BL, Prasai T, Singh A, Yami KD.Assessment of drinking water quality of Madhyapur-

Thimi and study of antibiotic sensitivity against bacterial

isolates. Nepal J Sci Technol 2009;10:167-172

2. Prasai T, Lekhak B, Joshi DR, Baral MP.Microbiological analysis of drinking water ofKathmandu Valley. Scientific world 2007;5:112-114.

3. Hasan N, Mirani ZA, Ismat S. Bacterial indicatorsof risk of disease from drinking water. BALWOIS. 2010;1-

5

4. Sharon O, Buce ID, Wayne W, Sherry W. Drinkingwater: Bacteria [online]. Available from:

http://extension.unl.edu/publication accessed 29

November 2013.

5. Marthie ME, Walda BZ, Dobromir NP, EtienneEM. Random survey of the microbial quality of bottled

water in South Africa. Water SA 2004;30:203-210.

6. World Health Organization. WHO Guidelines

for Drinking-Water Quality. 2nd ed. MicrobiologicalMethods. Geneva: Switzerland; World Health

Organization; 2001. Organization; 2001.

7. Aryal J, Gautam B, Sapkota N. Drinking water quality

assessment. J Nepal Health Res Counc 2012; 10:192-196.

8. Subedi M, Aryal M. Public perceptionabout drinking jar water and its bacteriological analysis.

Nepal Med Coll J 2010; 12:110-114.

9. Health Canada. Guidelines for Canadian Drinking Water

Quality: Guideline Technical Document. Ottawa, Ontario:

Canada; Health Canada; 2006.

Citing this article

Timilshina M, Dahal I, Thapa B. Microbialassessment of bottled drinking water of

Kathmandu valley. Int J Infect Microbiol

2012;1(2);84-86.

86

http://extension.unl.edu/publicationhttp://www.ncbi.nlm.nih.gov/pubmed?term=Subedi%20M%5BAuthor%5D&cauthor=true&cauthor_uid=21222409http://www.ncbi.nlm.nih.gov/pubmed?term=Aryal%20M%5BAuthor%5D&cauthor=true&cauthor_uid=21222409http://www.ncbi.nlm.nih.gov/pubmed?term=Aryal%20M%5BAuthor%5D&cauthor=true&cauthor_uid=21222409http://www.ncbi.nlm.nih.gov/pubmed?term=Subedi%20M%5BAuthor%5D&cauthor=true&cauthor_uid=21222409http://extension.unl.edu/publication